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Blood, 26 March 2009, Vol. 113, No. 13, pp. 2999-3007. Prepublished online as a Blood First Edition Paper on November 13, 2008; DOI 10.1182/blood-2008-07-166223. This Article Full Text Full Text (PDF) Supplemental Figure All Versions of this Article: blood-2008-07-166223v1 113/13/2999    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Azevedo, R. I. Articles by Sousa, A. E. Search for Related Content PubMed PubMed Citation Articles by Azevedo, R. I. Articles by Sousa, A. E. Related Collections Immunobiology Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  IMMUNOBIOLOGY IL-7 sustains CD31 expression in human naive CD4+ T cells and preferentially expands the CD31+ subset in a PI3K-dependent manner Rita I. Azevedo1,*, Maria Vieira D. Soares1,*, João T. Barata2, Rita Tendeiro1, Ana Serra-Caetano3, Rui M. M. Victorino1, and Ana E. Sousa1 1 Unidade de Imunologia Clínica, 2 Unidade de Biologia do Cancro, and 3 Unidade de Citometria de Fluxo, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal The CD31+ subset of human naive CD4+ T cells is thought to contain the population of cells that have recently emigrated from the thymus, while their CD31– counterparts have been proposed to originate from CD31+ cells after homeostatic cell division. Naive T-cell maintenance is known to involve homeostatic cytokines such as interleukin-7 (IL-7). It remains to be investigated what role this cytokine has in the homeostasis of naive CD4+ T-cell subsets defined by CD31 expression. We provide evidence that IL-7 exerts a preferential proliferative effect on CD31+ naive CD4+ T cells from adult peripheral blood compared with the CD31– subset. IL-7–driven proliferation did not result in loss of CD31 expression, suggesting that CD31+ naive CD4+ T cells can undergo cytokine-driven homeostatic proliferation while preserving CD31. Furthermore, IL-7 sustained or increased CD31 expression even in nonproliferating cells. Both proliferation and CD31 maintenance were dependent on the activation of phosphoinositide 3-kinase (PI3K) signaling. Taken together, our data suggest that during adulthood CD31+ naive CD4+ T cells are maintained by IL-7 and that IL-7–based therapies may exert a preferential effect on this population. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

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